It's hard to say but maybe the default Styles for the WPF controls don't get applied if you don't run it from a WPF app? We've seen this sometimes when customers use WPF Controls inside of a WinForms application. In that case, you need to create an instance of a WPF Application() object before referencing any UI controls if one doesn't already exist. I believe that gets things registered so styles will get applied. Maybe that will do the trick for your scenario.

Actipro Software Support

The latest build of this product (2018.1 build 0674) was released 1 month ago,
which was after the last post in this thread.